Blacksberry plant named &#39;Black Jack&#39;

ABSTRACT

The present invention is a new and distinct thornless blackberry cultivar named ‘Black Jack’, which is capable of producing large and firm fruit with high soluble solids. The cultivar is characterized by its thornlessness and its fruit attributes. It has the fruit morphology of other very large blackberries grown on thorny cultivars, namely uneven drupelets. It is, however, firmer than other large fruited types, and has very high soluble solids, up to 14%. ‘Black Jack’ plants are also unusual amongst the very large blackberry cultivars in that they produce commercial quantities of fruit, greater than 13 tons per acre on 2 year old potted plants.

FIELD OF THE INVENTION

This invention concerns a new and distinct cultivar of thornlessblackberry plant with a botanical name of Rubus spp. L. The new cultivaris distinguished from other cultivars by its combination of fruitfirmness, sweetness and size, and plant productivity and thornlessness.‘Black Jack’ is thereby suitable for premium fresh fruit marketing incommercial temperate zone production areas.

DESCRIPTION OF RELATED PRIOR ART

Several cultivars of blackberry plants are known. For instance, westernU.S. cultivars with an origin of the Rubus ursinus L or R. laciniatus:‘Marion’ (unpatented), ‘Cascade’ (unpatented), ‘Siskiyou’ (unpatented),‘Kotata’ (unpatented) and ‘Obsidian’ (unpatented), and ‘Onyx’ (U.S.Plant Pat. No. 22,358) have thorns and are trailing. ‘ThornlessEvergreen’ (unpatented) and its derivatives are trailing with deeply cutleaves. Of the upright or semi erect eastern blackberry cultivars withorigins from R. alleganiensis, R. cuniefolius and possibly R. argutus:‘Kiowa’ (U.S. Plant Pat. No. 9,861), ‘Chickasaw’ (U. S. Plant Pat. No.11,861), ‘Chesapeake’ (U.S. Plant Pat. No. 13,878), and APF-8, -12, and-45 (U.S. Plant Pat. Nos. 15,788, 16,989 and 22,449, respectively), arethorny. Several eastern thornless semi erect blackberry cultivars existincluding: ‘Merton Thornless’ (unpatented), ‘Thornfree’ (unpatented),‘Smoothstem’ (unpatented), Dirksen Thornless' (unpatented), ‘ChesterThornless’(unpatented), ‘Hull Thornless’ (unpatented), ‘Loch Ness’(unpatented), ‘Navaho’ (U. S. Plant Pat. No. 6,678), and ‘Nachez’ (U.S.Plant Pat. No. 20,891). ‘Black Jack’ fruit are much larger and have muchhigher soluble solids and less acid taste than all of these cultivars.Other thornless blackberry cultivars with erect or semi erect plants andlarger, lower acid, fruit are known to exist: ‘Arapaho’ (U.S. Plant Pat.No. 8,510), ‘Apache’ (U.S. Plant Pat. No. 11,865), ‘Ouachita’ (U.S.Plant Pat. No. 17,162) and ‘Drisblacktwo’ (U.S. Plant Pat. No. 22,002).Both ‘Drisblacktwo’ and ‘Apache’ are later ripening than ‘Black Jack’.‘Arapaho’ fruit has lower soluble solids and fruit weight. ‘Ouachita’fruit is smaller size, and also exhibits a slight drupelet sterility notfound in ‘Black Jack’. All of the above cultivars do not exhibit thecombination of fruit size, firmness and sweetness as ‘Black Jack’. Thenew and distinct cultivar of the present invention is a blackberry plantnamed ‘Black Jack’.

ORIGIN OF THE NEW CULTIVAR

The new cultivar of thornless blackberry originated from a controlledcross by Five Aces Breeding LLC of Oakland, Md. at its glasshousefacilities in Garrett Co., Md. The cross, designated: “PC”, was ‘LochNess’ (unpatented)×‘Sweet Peter’ (unpatented) blackberries (Rubus L.subgenus Rubus). ‘Loch Ness’ was produced at the Scottish Crop ResearchInstitute by Derek Jennings and ‘Sweet Peter’ was a plant growing in acontract grower's field that was planted in 1992. ‘Loch Ness’ is apremium floricane fruiting blackberry cultivar with high yield butsmaller, moderately firm, fruit. It is adapted to cooler climates suchas found in the United Kingdom. ‘Sweet Peter’ was selected as a parentfor its low acidity and plant vigor. Both crosses were geneticallythornless with presumed parents originating from the cultivar ‘MertonThornless’, an unpatented derivative of R. ulmifolius Schott. The crosswas made in the winter of 2008 and was given the year designation “C”;thus the progeny designation was “CPC”. CPC progeny seed from this crosswas exported to the United Kingdom, germinated and grown by EdwardVinson Ltd at their Sandbanks Farm, Faversham, Kent United Kingdom. Thepresent invention was first seedling of the CPC progeny selected in July2010 and was therefore designated “-1VB ” (selection one, VinsonBlackberry). Thus, the complete breeding designation of ‘Black Jack’ is“CPC-1VB”.

SUMMARY OF THE NEW CULTIVAR

This application relates to a new and distinct large fruited, thornless,blackberry cultivar, botanically known as Rubus L. subgenus Rubus. Thefollowing characteristics are outstanding:

1. Production of fruit which is very firm and has low acid taste andhigh soluble solids.

2. Production of very large thick fruit, up to 4 cm in length, with aratio of width to length averaging 4 units wide to 5 units long; or thediameter width is 80% as compared to the length of the fruit.

3. The season of production can exceed 6 weeks as long basal fruittrusses readily occur.

4. ‘Black Jack’ canes are vigorous, floricane-fruiting and completelythornless.

These characteristics make ‘Black Jack’ suitable as a mid-summerthornless blackberry for premium fresh fruit marketing in commercialproduction areas with at least 500 hours of chilling.

Overwintered ‘Black Jack’ plants with floricanes in southern Spainproduced insufficient bud break after 250 chilling hours. In controlledchilling tests, ‘Black Jack’ floricanes had sufficient bud break after500 hours chilling, similar to other moderate chilling blackberrycultivars such as Arapaho and Shawnee, but more than Choctaw and Kiowa(U.S. Plant Pat. Nos. 8,510, 5,686, 6,678, 9,861 respectively).Floricane fruit production has not been tested in areas that experiencesignificant sub freezing temperatures, therefore, no claims are madeconcerning cold hardiness below −7° C.

The following characteristics are useful in distinguishing this cultivarfrom other cultivars and can be useful for cultivar identification.Plants used for these observations were grown in uncrowded conditionsand in full sunlight.

1. Canes are completely thornless and semi upright after the firstgrowing season.

2. Floricanes produce fruit which is very large, firm, does not bleedand is very high in soluble solids.

3. Fruit can be borne on normal apical and mid floricane trusses andlong trusses arising from basal floricane buds which produce a latercrop.

4. Fruit is relatively thick, with a diameter 80% of the length of thefruit.

5. Fruit is attractive, but exhibits some drupelets which are recessedproducing an uneven fruit surface.

BRIEF DESCRIPTION OF THE PHOTOGRAPHS

The accompanying photographs show typical characteristics of the newvariety:

FIG. 1. shows the vigor and growth habit of one year old tissue culture‘Black Jack’ plants grown on single stakes in a tunnel in pots in theUnited Kingdom.

FIG. 2. shows the thornlessness of a ‘Black Jack’ primocane and 2001Royal Horticulture Society Color Plate 144.

FIG. 3. shows the top surface of a ‘Black Jack’ leaf with 2001 RoyalHorticultural Society Color Plate 147 and the pattern of leaf attachmentand leaf blade smoothness and veination.

FIG. 4. shows the red blush on a thornless petiole from the leaf on a‘Black Jack’ primocane with 2001 Royal Horticultural Society Color Plate184B.

FIG. 5. shows a flower cluster of ‘Black Jack’ at various stages ofopening. FIG. 6. shows 20 gram plus size ‘Black Jack’ fruit withpersistant red blushed styles and uneven drupelet size.

DESCRIPTION OF THE NEW CULTIVAR

The following is a detailed description of ‘Black Jack’, the newcultivar, including fruit production, together with the cultivar'smorphological characteristics. ‘Black Jack’ is a species hybrid, whichcontains a predominance of Rubus L subgenera Rubus blackberry traitsfound in its supposed eastern North American progenitor species, Rubusallenganiensis and R. argutus. It also exhibits several traits of itsthornless parent species, R. ulmifolius Schott. It is therefore similarin leaf, cane and flower form to many of the other eastern semi-erect toerect thornless blackberry cultivars.

The description is based on information from plants grown in fields atFaversham, Kent, England and from plants grown in the Five Aces Breedinggreenhouse at Oakland, Md. As these climates differ, particularly intemperatures experienced in the growing season, we believe thedescription of ‘Black Jack’ will be consistent in other locations.

‘Black Jack’ produces vigorous primocanes which are trailing to semierect in the first year after transplant (FIG. 1). After plantestablishment in the first year, new primocanes are erect to semi-erect.Fall growth of primocanes can be “rat-tailed” and typical of thetip-layering response of most blackberries. ‘Black Jack’ produces amoderate number of root suckers (approximately 1.3 per plant) in secondand subsequent years after transplant, typical of eastern thornlessblackberry plants, but less than thorny cultivars. New primocanes areformed from the crown and average 4.1 per plant in the second year afterfield planting. During the growing season, canes are medium yellow-greencolored (2001 Royal Horticultural Society Color Plate No. 144A) with ared blush (2001 Royal Horticultural Society plate No. 184B) on less than5% of the cane (FIG. 2). Canes on small plants can have much higherpercentages of blush, especially when grown at lower nutrient levels inthe field.

Vigorous canes usually branch, forming on average 3.4 branches when thecanes branch. When growth averages 2 m per cane, branching will occur on24% of the canes on young plants. On 2 year old potted plants, 50% ofthe canes are unbranched. This is less than expected for thorny easternblackberry cultivars and typical of eastern thornless blackberrycultivars. Average total node number per cane is 42.4 for second yearadult, non-tissue culture plants. Growth is moderately vigorous,reaching on average 278.8 cm in full sun. Internode length at 30 cmabove ground in well lighted plants without floricanes is 6.3 cm. Canediameter at the same location was 1.6 cm. ‘Black Jack’ nodes producemostly single buds; when secondary buds occur, they are basal to themain bud and much reduced in size compared to the primary bud.

Thorns are completely absent (FIG. 2). Cane waxiness is slight, lightrubbing will result in waxy reflection in the sun. Canes do not normallyexfoliate or crack during the growing season. Canes have short silverypubescence which is noticeable, but not downy.

The lower surface of ‘Black Jack’ leaves is pubescent gray-greenresembling 2001 Royal Horticultural Society Color Plate No. 137C. Theupper leaf is dark green, most closely in hue to 2001 RoyalHorticultural Society Color Plate No. 147A (FIG. 3), depending on theamount of N fertilization and time of season. Senescing leaves have agreen-yellow color resembling 2001 Royal Horticultural Society ColorPlate No 152A when senescence begins to occur after frost or in lateOctober. Leaf abscission accelerates when temperatures less than −5° C.occur in fall. Petiole and petiolule color is similar to that of theprimocane (2001 Royal Horticultural Society Color Plate No.144A). Blushcolor on some canes and petioles can reach over 95% in the fall; the redcolor resembling in hue 2001 Royal Horticultural Society Color PlateNo.184B) (FIG. 4).

Vigorous plants have leaves that are 90% pentafoliolate in the lower 30cm of the primocane. Above 30 cm, 95% of the leaves are pentafoliolate.The pentafoliolate terminal leaflet is, on average, 12.65 cm wide and11.28 cm long. The trifoliolate terminal leaflet is, on average, 7.7 cmwide and 8.7 cm long. The pentafoliolate maximum leaf width, measuredfrom apex of a lateral leaflet to the opposite lateral leaflet apex is,on average, 28.05 cm. The trifoliolate maximum leaf width, measured fromapex of the lateral leaflet to the opposite lateral leaflet apex is, onaverage, 17.44 cm. Average lateral leaflet widths, at their widest pointand on the largest lateral leaflet, were 6.4 cm and 6.2 cm forpentafoliolate and trifoliolate leaves, respectively. The pentafoliolateleaf petiole, basal petiolule and apical petiolule lengths averages 8.1cm, 0.5 cm and 4.0 cm respectively for a total of 12.6 cm. Lateralleaflets are sessile and join at the petiole apex with the apical leafpetiolule (FIG. 3). This produces a palmate-pinnate pentifoliolatecompound leaf. The trifoliolate leaf petiole and petiolule lengthsaveraged 4.2 cm and 2.3 cm respectively. Petiole widths are 0.38 cm and0.22 cm for pentafoliolate and trifoliolate leaves respectively. Leafserration is simple sawtooth; leaves have little laminar leaf puckeringwith a distinct depression directly above the midrib and secondary veins(FIG. 3). The veination pattern is otherwise common for most cultivarsof blackberry and cannot be used to distinguish this cultivar. Leaveshave stipules at their petiole base, averaging 4 mm long and 0.3 wide.

‘Black Jack’ floricanes are similar to primocanes in color, resemblingin hue 2001 Royal Horticultural Society Color Plate No. 144A (FIG. 2).Blush color on some canes and petioles can reach over 95% in the fall;the red color resembling in hue 2001 Royal Horticultural Society ColorPlate No.187A. The floricane epidermis cracks to a moderate amount andonly at the cane base, with 1-5 cm long, 0.5 cm wide fissures runningparallel with the cane. These fissures do not have exfoliating edges.The internal color of the fissures resembles 2001 Royal HorticulturalSociety Color Plates 1996, 199C and 199D.

Flower trusses can appear at any floricane node. Each cymose flowertruss averages 12.2 nodes totaling 36.3 cm in length. Of these trussnodes, 6.6 have flowers on average; non-productive nodes are always atthe flower truss base. The number of flowers per truss averages 9.0 inthe apical part of the cane and 12.8 in the basal part of floricanes on2 year old plants. For 3 year old plants, the numbers of flowers pertruss is 8/ on average over the whole cane.

Flower trusses average 4.77 monofoliolate leaves, 6.33 trifoliolateleaves and no pentafoliolate leaves. Monofoliolate leaves averaged 5.8cm in length and 5.6 cm in width. Monofoliolate leaves had 2.6 cm longand 0.18 cm diameter petioles with 0.8 cm long, 0.2 cm wide stipules. Onflower trusses, the terminal leaflet on trifoliolate leaves averaged 7.2cm in length and was 5.9 cm in width. Width of trifoliolate leaves, fromlateral leaflet to lateral leaflet, was 11.34 cm. The average maximumwidth of the largest lateral leaflet was 4.4 cm. The length of thepetiolule was 1.4 cm and the petiole length was 3.5 cm with a diameterof 0.3 cm.

The unscented flower morphology and early fruit morphology is typical ofmost eastern thornless blackberry cultivars, having five pink (2001Royal Horticultural Society Color Plate No. 69A) petals that average 1.3cm long and 0.8 cm wide (FIG. 5). Eventually these petals turn white(2001 Royal Horticultural Society Color Plate No. 155D) and abscise daysafter pollination. Flowers have five 0.7 cm long, 0.48 cm wide at thebase triangular gray-green and pubescent sepals (2001 RoyalHorticultural Society Color Plate No. 137C). The outer edge of the sepalis distinctly lighter colored than the center section due to anabundance of downy hairs producing a pair of minute framing stripes tothe leaf-like appendage. Sepals are longer on primary fruits and alwaysremain on the plant after fruit harvest. Flowers are borne on 3.2 cmlong thornless peduncles which resemble in hue 2001 Royal HorticulturalSociety Color Plate 144A. Peduncles on basal flower trusses are shorter,averaging 0.8 cm in length.

‘Black Jack’ flowers have on average 71.6 pistils on midseason fruit anda similar number of anthers, 61.0. The anther stalk is light green-white(2001 Royal Horticultural Society Plate 157C). Larger flowers average158 pistils. The pistil style initially is green-white (2001 RoyalHorticultural Society Plate No. 157A) but at harvest, it becomes mediumgrayed-yellow (2001 Royal Horticultural Society Plate No. 161A) withmost developing a red blush (2001 Royal Horticultural Society Plate No.51C) on half the stylar stalk. The stylar stalk is persistent on ripefruit and contrasts in color with the fruit flesh. The initial orprimary fruit are easily distinguishable by long thick oval shape forthis variety at 12 days post pollination. Fruit ripens from green (2001Royal Horticultural Society Plate No. 144A) to blush red, to full red(2001 Royal Horticultural Society Plate No. 184B and 184C) at immatureand shiny then dull black (2001 Royal Horticultural Society Plate No.202A) at full ripe (FIG. 6).

Fruit weight averages 14.47 grams, ranging from 9.8 to 24.0 grams. Fruitlength averages 3.3 cm long and 2.6 cm in diameter on apical flowertrusses. Fruit is somewhat larger on basal long trusses averaging 3.9 cmlong and 3.0 cm in diameter. Receptacle diameter at the abscission zoneis on average 0.52 cm regardless of the fruit origin on the plant. As inall blackberries, the receptacle is carried along with the drupelets asa harvested ripe fruit. ‘Black Jack’ fruit are cohesive and firm andwill not leak pigment in normal transport and storage. ‘Black Jack’ islow in acid by taste and high in soluble solids by refractometer,averaging 11.3% brix over the whole season with a range of 9 to 14% on 2year old plants. ‘Black Jack’ drupelets are not uniformly distributed insize and presentation on the fruit; this produces a less than regularsurface (FIG. 6). This characteristic is similar to other large fruitedblackberries, for example the thorny cultivars, ‘Kiowa’ and‘Chesapeake’, and is typical for ‘Black Jack’.

Without tunnels, fruit is ripe beginning the last week in July in Kent,United Kingdom where the 5% ripe date in 2012 was July 27. Fruit harvestlasts until late August with the 95% ripe date of 20 Aug., 2012. This isearly midseason and comparable to ‘Loch Ness’.

FRUIT PRODUCTION

‘Black Jack’ has been tested in a potted plant trial in Kent. Thefollowing data were collected in the summer of 2012. Total floricaneyield was 6.2 lbs per plant on 2 year old plants with 86% class 1 fruitand 3.5 lbs per plant on 1 year old plants with 77% class 1 fruit. ‘LochNess’, a very high yielding type for the United Kingdom, averaged 4.4lbs per plant with 75% class 1 fruit. A yield of 6.2 lbs per plant isequivalent to 26,832 lbs per acre at 10 ft between rows.

‘Black Jack’ can be asexually propagated by tissue culture, tip layeringor root suckers. No off-type plants have been observed in the history ofasexual propagation of this cultivar by any method.

What is claimed:
 1. A new and distinct thornless floricane-bearingblackberry plant known as ‘Black Jack’ as described herein; illustratedand identified by the characteristics set forth above.